Filter Concept Pvt Ltd Basics of Filtration Process

Filter Concept Pvt. Ltd

Basics of Filtration (Process Filtration)

Reasons For Filtration § Removal of fluid contaminants • Eliminate costly problems • Filtered product more valuable • Increase product yield § Collection of suspended solids • Catalysts recovery • Reduce operating cost

Driving Forces § Filtration The removal of a suspended particles from fluid, liquid or gas by passing a fluid through a porous or semipermeable medium § Separation

Other Driving Forces • • Gravitational Settling Centrifugal Vacuum Advantages • • • Greater output Small equipment required Ease in handling volatile liquids Pressure Drop • • • System pressure drop Cartridge pressure drop Housing pressure drop

Filtration Variables • Flow rate • Differential pressure • Viscosity • Contaminants • Flow conditions • Compatibility • Area

Flow Rate • Size determined by the cartridge In most of the cases, the flow rate and /or capacity needs of the application will be used to determine the appropriate size of cartridge. The housing will then be sized to fit the selected Cartridge • Inlet /Outlet The inlet /outlet pipe size is also selected to meet the flow rate requirement. In most cases this is already determined by the pipe size in the system

Differential Pressure • Difference in pressure between the inlet & outlet sides of a filter • Measured as PSI or k. Pa and referred to as PSID ∆P, pressure drop or differential pressure • For applications sensitive to pressure drop, housing & cartridge need to be considered ∆P= ∆P Cartridge + ∆P Housing

Location • The size of the housing may be influenced by the amount of space available for the installation • Location and product selection can also be influenced by the surrounding environment

Dirt Holding Capacity Dirt holding capacity is measure of the weight gain of a filter during its useful (as measured by pressure drop at a given flow rate ) life.

Systems § Open • Effluent to atmosphere § Parallel • Two or more systems • Higher flow rates • Reduced pressure drop § Series • Two or more systems • Step filtration

Parallel System

Series System

Mechanical capture § Direct interception Physical barrier capture § Bridging Two particles hitting the filter medium at the same time creating a smaller pore

Mechanical Capture § Sieving Particle too large to pass through pore § Inertial impaction Inertia principle § Diffusion interception Primarily found in gases

Mechanical Capture § Electro kinetic effects Electrically charged filter medium § Gravitational settling Heavier particles settled at bottom

Means Of Retention § Mechanical retention Particle restriction from passing through medium § Adsorptive retention Adherence of particles to medium

Media Migration & Particles Migration • Media migration is the sloughing of the filter medium into the filtered fluid • Particle migration is the sloughing of filtered particulate matter from the filter cartridge into the filtered fluid. This occurs most often due to changes in the flow rate or excessive pressure drop

Cartridge flow § Radial flow • Pleated • String wound • Polypropylene spun • Paper carbon • Carbon black • Granular Carbon • Specialty

Cartridge Flow § Up flow • Granular carbon • Specialty ØSoftener ØDI ØIron reduction

§Means of retention • Surface ØParticles on the surface of medium forming a cake

Surface filters • Surface filters remove particulate matter via a sieving mechanism. (you can’t push a basketball through chicken wire. ) • The media is usually pleated to provide the maximum amount of surface area.

§Means of retention • Depth ØParticles trapped throughout the depth of medium

Depth Filters • Depth filters remove particulate matter via a tortuous path. The fluid travels racially through the depth of the cartridge. • Depth cartridges normally have a graded density. They have larger openings at their surface and smaller openings near their center.

Surface vs. depth filters • In theory a surface filter will work better when the particulates matter in the water are of the same size. • A depth filter will work better when the particulate matter has abroad range of sizes and the filter truly has gradient density.

Performance Factors • Filtration efficiency and micron rating • Dirt holding capacity • Pressure drop • Media migration & particles migration • Chemical compatibility

Parameter Surface Filters Depth Filters Deformable Particles May blind off pleats Recommended-Adsorptive retention Non-deformable Particles Removes narrow range Removes broader range of particles Rating Absolute or nominal Classification/ Clarification Classification Clarification Flow per 10 equivalent PSID Recommended 10 gpm Recommended 5 gpm Economics-Particle Retention < 10 micron Holds more dirt than depth, handles higher flow rate More economical than pleated at greater than 10 microns Cartridge Cost More expensive initially than depth, fewer replacements, holds more dirt More economical initially than pleated, holds less dirt Housing Cost Fewer cartridges-smaller More cartridges-bigger housing

Type of cartridge Description Benefits Typical Application Yarn Wound ( Depth ) Yarn of twisted staple fibers wound around a center core. Inexpensive, broad chemical compatibly, numerous material options for many applications. Chemicals, magnetic coatings, Cosmetics , oil production , food and beverages , potable water , photographic applications Non –Woven ( Depth ) Depth media crated by layering melt brown ( extruded ) fibers Graded pore structure, Photo chemical , potable water, chemically inert materials , solvents , ultrapure water No extractable downstream. , chemicals , beer & wine, food and beverages enzymes, resins Non – Woven Pleated ( Surface ) Pleated media ; spun bonded or melt brown sheets , paper like Wide chemical compatibility , large surface area per 10” cartridge, high dirt holding capacity , cheaper than depth , cartridge at low microns DI water , Process water, electronics , wine filtration , photographic applications, magnetic coatings, chemical s, cosmetics. Membrane Polymeric sheets containing symmetric or asymmetric pores ( RO membrane and most UF membranes don’t have pores ) Asymmetric pores , Positive mechanical retention , high flow rate, absolute ratings , resistance to bacteria, ultra –fine filtration DI water applications, electronics , plating, chemical process , power generation, photo graphic applications, food and beverages, various etch baths.

Type of cartridge Description Benefits Typical Application Resin – Bonded Fibers Treated with resin to enhance rigidity Rigid for high viscosity, no center core, no glues or epoxies, little media migration, one piece construction , high flow rates Paints , inks , coatings , adhesives, oils , sealants, resins , petroleum, Pesticides, salt water, varnishes Sintered Metal Porous media formed by sintering thin layer of metal Absolute rating, strength, porosity, Clean ability , high flow and dirt holding capacity , non fiber releasing High temperature, high pressure applications , corrosive fluids, polymer filtration , process steam, gas filtration , catalyst recovery Woven Metal Fibrous media woven into distinct pattern Strength, clean ability, high flow porosity, dirt holding capacity Same as Dynalloy but at much larger micron ratings. Used more as s sieve Granular Porous carbon activated to develop large surface area Removes dissolved organics from gas and Potable water , reverse osmosis , organic

Fiber filtration • Fiber diameter Thinner fibers equal finer filtration • Porosity Ratio of void volume to total volume of medium • Thickness of media Thicker medium equals decreased pore size

Industrial water requirement Product Unit Produced Gal. /Unit Water required /Gal. /Day Office Person - 27 to 45 Hospital Bed - 130 to 350 Hotel Guest room - 300 to 525 Commercial 1 b. Work load 5 to 8 - Institutional 1 b. Work load 1 to 4 - Restaurants Meal 1 to 4 - Packing house 100 hogs killed 550 - 600 - Slaughter house 100 hogs killed 550 -600 - Stockyard 1 acre 160 -200 - Poultry 1 Bird - 1 100 bbl 75000 to 80000 Buildings Laundries Meat Oil Refining

Product Unit Produced Gal. /Unit Water required /Gal. /Day 1 b. Sugar 1 - 1 ton 40, 000 - Ground wood 1 ton (dry) 5000 - Soda 1 ton (dry) 85, 000 - Sulfate 1 ton (dry) 65, 000 - Sulfite 1 ton (dry) 60, 000 - Cotton Bleacheries 1 lb. double boil 25 to 40 - Cotton finishing 1 Yard 10 to 15 - Silk Hosiery dyeing 1 lb. 3 to 5 - Sugar Refinery Paper mill Paper Pulp Textile Knit goods bleaching

Chemical compatibility Several sources are available to check the compatibility of housings for use with fluids other than water. Remember to check all materials in the cap, sump, O-ring, and cartridge.

Chemical Temp % Conc. PP TP SAN Nylon GP ABS GP Delrin Buna-N Silicone Viton B-60 300 Series SS Acetic Acid 125 90 A A D C - Acetone 125 100 A D B D B D A Ammonium Compounds 125 100* A A A* A B A C Ammonium Hydroxide 125 10 A A D A - A C Beer 125 Any A A D B A D C A A Benzene 72 100 B D A D B D - A B Calcium Compounds 125 Any* A A A C A B/C Calcium Hypochlorite 68 20 A - D B C A D Citric Acid 125 10 A A C B A D C A - Cottonseed Oil 125 - A A A B A A - A B Detergents 125 2 A A A - A - Ethyl Alcohol 125 96 A B A - Freon 68 25 B Fruit Juices 125 - A A A - A A Gasoline 125 100 C A A D B A D A A Glucose 125 20 A A A B A A Glycerin 125 100 A A A B A A Glycol 125 - A D - D A A - Hexane 125 100 C - A D D A B A A Hydrochloric Acid 125 20 A A D B D C - A - Hydrofluoric Acid 68 40 A - D A D D - A D D

Chemical Temp % Conc. PP TP SAN Nylon GP ABS GP Delrin Buna-N Silicone Viton B-60 300 Series SS Hydrogen Peroxide 68 30 A - D D - A - Inks 125 - A B A A - A A Ketones 68 - D D B - C D - D A Lubricating Oils 125 100 C A A B A A C A A Mercury 125 100 A - A A Methyl Alcohol 125 100 A D A B - C - Mineral Oil 100 B A A A - A A Naphthalene 125 100 A B A C D B D A A Nitric Acid 68 10 A B D C D D - A A Olive Oil 125 100 A A A C A A Plating Solutions 125 - A_ - A/D* - - A_ D A - Sodium Compound 125 Any A A A/C* C - A C A B Sodium Hypochlorite 100 5 A A A B A A C A B Sugar & Syrups 125 - A B A A A Sulfuric Acid 68 25 A A D B D C - A - Toluene 100 - D D A D D C A Water (hot) 200 100 - - A - - C A B A DI Water 125 100 B A A A A - Sea Water 125 100 A B A A C A - Whiskey/ Wine 125 - A A A - A A Xylene 100 C D A D D A A

Temperature • Standard polypropylene housings have a maximum temperature rating of 125°F (52°C). • Glass reinforced nylon housings have a maximum temperature rating of 165°F (74°C). • All Housings should be protected from freezing.

Temperature Gasket Material Filter Media Housing media Buna – N 250˚ F (121˚C) Ethylene Propylene 350˚ F (177˚C) Viton 450˚ F (232˚C) Teflon 500˚ F (260˚C) Polyester 300 ˚F (149˚C) Polypropylene 200˚ F (93˚C) Nylon 300˚ F (149˚C) Carbon Steel 300˚ F (149˚C) 304 Stainless steel 300˚ F (149˚C) 316 Stainless steel 300˚ F (149˚C) PVC 150˚ F (65˚C) Polypropylene 125˚ F (52˚C)

Filtration efficiency and micron rating • There is a big difference between absolute and nominal rating • In most cases a nominally rated filter is adequate. • A filter’s efficiency is the percentage of particles of a specific size (microns) that it will remove • Filter efficiency is dependent on flow rate • A nominal micron rating is generally accepted to mean the particle size at which the filter is 85% efficient • An absolute micron rating is generally accepted to mean the particle size at which the filter is 99. 99% efficient

Micron Size Particle Size Table salt 100 microns Human Hair Talcum Powder 40 - 70 microns 74 Microns 2 Microns 5 Microns 10 microns 8 Microns Fine test dust 0. 5 - microns Pseudomon as diminuta 0. 3 - microns 44 Microns 325 Mesh 200 Mesh 145 Microns 100 Mesh 25 Microns Magnified 500 times

Filter Efficiency • A filter’s efficiency is a function of the beta ratio Beta ratio % Efficiency 1 0 2 50 4 75 5 80 10 90 20 95 50 98 75 98. 67 100 99 1000 99. 9 5000 99. 98 10000 99. 99 Infinity 100